Issue with Planner task duplication when Assignments are selected

Hello @Saltanat Kolesnichenko,

Thank you for your question.

To better understand the behavior and determine whether this is related to a synchronization issue or a known limitation, I would like to gather a bit more information from your side.

First, could you please confirm whether you are using Planner within the Teams app. If so, I recommend trying the same steps using Planner on the web (tasks.office.com) and checking whether the issue occurs there as well. This will help us determine if the behavior is related to the Teams client or the Planner service itself.

Additionally, could you let me know if this issue occurs when copying tasks to one specific plan, or if it happens consistently across any target plan. For example, does it also occur if you copy the task within the same plan or across different plans.

As another test, it would be very helpful if you could:

• Create a new test plan
• Create a simple test task in that plan
• Try copying the task with Assignments selected

This will help us identify whether the issue is related to a specific plan/template or more general behavior.

Once I have this information, I’ll be in a better position to assess whether this is expected behavior, a sync-related issue, or something we may need to investigate further.

Thank you for your cooperation, and I look forward to your update.

Kind regards,

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Assignments can be copied with tasks in Planner, but there are important limitations that affect what appears in the destination plan.

From the documented behavior of task copy in Planner:

• Assignments are not copied by default; they must be explicitly selected during the copy process.
• Assignments cannot be copied across plans that belong to different Microsoft 365 groups because the memberships differ.
• When copying to a plan that is shared with a different Microsoft 365 group, the Assignments field is not supported for copy.

Relevant matrix for copying tasks:

• Copy within the same plan: Assignments = Yes (supported)
• Copy to a plan shared to the same Microsoft 365 group: Assignments = Yes (supported)
• Copy to a plan shared to a different Microsoft 365 group: Assignments = No (not supported)

This means:

• If the source and target plans are in different Microsoft 365 groups, selecting Assignments during copy is not supported. In such cases, the task copy operation may fail or behave unexpectedly, which aligns with the symptom where the copied task does not appear when Assignments is selected.
• When copying within the same plan or to another plan in the same group, Assignments can be copied, but they are still off by default and must be turned on in the copy dialog.

Answers to the specific questions:

• Is this a known issue or limitation?
  • It is a documented limitation that Assignments cannot be copied across plans that belong to different Microsoft 365 groups. This is due to differences in group membership.
• Recommended workarounds or permanent fixes:
  • Ensure that source and target plans are in the same Microsoft 365 group if Assignments must be copied.
  • If copying to a plan in a different group, copy the task without Assignments, then manually reassign users in the destination plan.
  • For repeated use, consider keeping templates in a plan that shares the same group as the target plans so that Assignments can be reused where supported.

References:

• Copy and move Planner tasks